Building of Amorphous Cu x O With Cu─O─Si Interface for CO ₂ Reduction to C ₂₊ Products

Amorphous copper‐based catalysts with a large number of undercoordination sites exhibit promising catalytic performance for the electrocatalytic CO 2 reduction reaction (eCO 2 RR). However, their structure stability of amorphous Cu x O is significant for achieving high‐efficiency catalytic performance and excellent stability. Herein, amorphous Cu x O nanoparticles embedded uniformly in mesoporous silica spheres (Cu x O@mSiO 2 ) were fabricated via a modified Stöber method combined with in situ electrochemical pre‐reduction. Experimentally, the Cu─O─Si interface suppresses the over‐reduction of CuO to metallic Cu and modulates the electronic structure of Cu species. It can be demonstrated that the resulting amorphous Cu x O switches the adsorption of * CHO and * OCCO intermediates from conventional Cu‐anchoring configurations to lattice oxygen‐anchoring counterparts, significantly weakening the thermodynamic restriction for post‐CO coupling toward C 2+ pathway. Ideally, the Cu x O@mSiO 2 ‐0.4 catalyst achieves a C 2+ Faradaic efficiency of 40.1% with a partial current density of −10.8 mA∙cm −2 at −1.7 V vs. RHE, which is two times greater than that of crystalline CuO‐derived Cu. Furthermore, Cu x O@mSiO 2 maintains stable catalytic activity and selectivity over 9 h of continuous eCO 2 RR reaction.